This invention relates to oxidizing solutions for use in liquid/solid hybrid rocket motors.
A liquid/solid hybrid rocket motor is a rocket motor in which a liquid is reacted with a gas formed by the combustion of a solid propellant to produce thrust. Two types of liquid/solid hybrid rocket motor are possible. The most common type of liquid/solid hybrid rocket motor employs a solid propellant which produces a fuel-rich gas and a liquid oxidizer. The second type of liquid/solid hybrid rocket motor employs a solid propellant which produces an oxidizing gas and employs a liquid reductant. This invention is applicable to liquid/solid hybrid rocket motors which employ a liquid oxidizer.
Liquid/solid hybrid rocket motors may be classified by the reaction chamber in which the liquid reactant is reacted with the gas formed by the combustion of the solid propellant. A "primary chamber" liquid/solid hybrid rocket motor reacts the liquid reactant in the same reaction chamber which contains the solid propellant. A "secondary chamber" liquid/solid hybrid rocket motor reacts the liquid reactant in one or more "secondary" reaction chambers, which do not contain solid propellant. This invention is applicable to both primary chamber and secondary chamber liquid/solid hybrid rocket motors.
Liquid oxidizers are preferred over gaseous oxidizers because of volume limitations. A liquid oxidizer should possess several properties. It should react energetically and easily with the fuel. It should not be corrosive or require cryogenic temperatures to exist in the liquid state. It should not be hazardous during preparation or long-term storage. It should be stable over long-term storage. Reasonable viscosity is important since a liquid oxidizer must flow readily through piping and be capable of injection through a spray nozzle without the use of high pressure pumps.
Various liquid oxidizers have been considered for use in liquid/solid rocket motors, including liquid oxygen, liquid ozone, liquid fluorine, chlorine trifluoride (ClF.sub.3), red fuming nitric acid, dinitrogen tetroxide, and hydrogen peroxide. There are safety, storage, or handling problems associated with each of these oxidizers. Liquid oxygen and liquid ozone require cryogenic storage and handling. Hydrogen peroxide, liquid fluorine, chlorine trifluoride, and red fuming nitric acid are corrosive and therefore require special materials, storage, and handling. Chlorine trifluoride will react spontaneously upon contact with air. Dinitrogen tetroxide will volatize unless external pressure is applied.
Hydroxylammonium salt solutions are commonly employed in the preparation of oximes from ketones or aldehydes and, in particular, the preparation of cyclohexanone oxime from cyclohexanone. See C. van de Moesdijk, "Cyclic Process For The Preparation And Processing Of A Hydroxyl-Ammonium Salt Solution," U.S. Pat. No. 4,328,198 (May 4, 1982).